Electron tube system



Sept. 19, 1933. s. Y. WHiTE ELECTRON TUBE SYSTEM Original Filed May 1, 1950 Snvewtoz \S/D/VL X X WH/Tf WIT/V5155 Patented Sept. 19, 1933 1,927,560 7 ELECTRON TUBE SYSTEM Sidney Y.

White, New York N. Y.,

Edward H. Lofti n, trustee assignor to Application May-1, 1930, Serial No. 448,339 Renewed February 2, 19 32 V 9 Claims.- (Cl. 250-27) This invention relates to direct coupled cascaded electron tube systems, and more particularly to improvements in the direct coupled electron tube systems disclosed in my copending application Serial Number 381,754, filed July 29,

An object of my invention is the attainment of either the detection of high frequency modulated currents or substantially linear with frequency l0 amplification of audio frequency currents within one direct coupled tube system without change in the constants of the circuits when changing from a source of one type of signal to the other.

Another object of my invention is the alternating current energization of such a direct'coupled tube system with hum in the output of the system reduced to a minimum.

Further objects of my invention will become apparent as the description of my invention as diagrammatically illustrated in the accompanying drawing is developed.

For the sake of simplicity and definiteness I shall give the constants of my improved circuit arrangement, but it is to be understood that these 5 constants may be variedto adapt the same to use with various tubes without departing from the spirit of my invention. v Referring to the drawing RT designates a full-wave rectifier tube of the 80 type enerv gized from a source of 110 volt alternating cur-- rent AC through a power transformer PT, the rectifier delivering a potential of about 425 volts between the positive terminal P and the nega: tive or grounded terminal G. a In shunt to the terminals P and G of the rectifier I have provided a filter systemincludingfilter condensers FC1 and FCz of 1.0 microfarad capacity each, between which is located a filter choke coil FCh having an inductance of about 20 henries. a I

In series with the filter choke coil FCh between theterminals Pand G of therectifier I have connected the primary of an output trans-- former OT, the. secondary of which is connected to the voice coil of an electrodynamic loud speaker LS, a radio frequency choke coil RFCh,

the plate to cathode path of tube VT2, a type -45 V output tube, the filament of which is energized by a filament heating transformer HT2 centertapped as shown at CTz'and a resistance R of about 6100 ohms. Between the filter choke coil F071. and the center tap CTz I have connected two non-inductive series resistances R and R'f having a value of about 100,000 and 25,000 ohms respectively. f

The tube VTiof the -:24type includes a. cathode which is energized froma heating current transformer HT1 the secondary of which is connectedto the point A on the resistance-R of a value of about 425 ohms from the terminal G of the rectifier. The cathode proper is connected 'to the terminal G through a non-inductive .stabilizing resistance SR of about 50,000 ohms. t

- The screen grid of tube VT1 is connected to the point B on the resistance'R of'a valueof about 65. 1400 ohms from the terminal G." .The plate of tube VTriS connected directly by a unipotential connectionto the grid of tube VTz and 'to the point between the resistances R, R thorugh a non-inductive resistance OR of .a value of-about ,megohm.

The grid of tube.VT1-is connected througha phonograph pick-up or similar device with a shorting-switch SW and a tunable circuit includ: ing a secondary Sand'tuning condenser TC'to they point A on the resistance R, a signal current path being provided to the cathode'through a. signal current condenser SCi of avalue of 1.0 microfarads. 1

The resistance Ris shunted with a condenser R0 of a value of 1.0 microfarads capacity,.to bypasssignal currents in the resistance R and a condenser SCz of 1.0 microfarads capacity isv provided across the resistancesR and R to.complete the signal currentoutput circuit ofltube VTz, high frequency currents being shunted out of the output circuit by means of the condenser RFC of amout 0.0005 microfarad capacityconnected between-th plate and center-tap (3T2 of tubeVTz. '7 3 Hum withinthe system is controlled by developing hum current potentials in the stabilizing resistance SR by means of the condenserI-IBC of 1.0 microfarads capacity connected to the variable tap D on the resistance R.

The operation of this system is as follows. When the constants'hereinbefore set forth are used the spacecurrent'of tube VT2 is approximately 30milliampere's and the plate cur'rentof 3 tube VT1 about 225 microamperes.

The stabilization efeaturesof this circuit are fully described in my copending application here-j inbefore referred to and are'briefly summarized here as follows; The biasfor the whole system is determined by the differential voltagebetween the cathode" of tube VTiand the point A on the, resistance .R which differential voltage isdeter mined by thevoltages produced by the space current of tube VT1 flowing through the resistance SR and the space current of the tube VT2 flowing through the resistance R.

Should the voltage of the source AC fluctuate even through wide limits of or more volts higher or lower than the rated 110 volts there is produced a change in the plate current of tube VTz, which change in space current changes the potential of the point A with respect to ground and with respect to the cathode of tube VT1 so that the grid of tube VT1 becomes more positive or negative with respect to the cathode thereof causing more or less space current to fiowthrough the tube VT1. This change in space current flow ing through the resistance CR automatically adjusts the'bias of the grid of tube VTz to coin-v pensate for this change.

If the introduction of signal current p aten-- tials at PU or S causes a change in the average bias of the grid of tube VT1 causing a change in the average space current thereof this is reflected into the space current of tube VTz which in turn re-establishes the potential of the point A with respect to the cathode of tubeVT1 compensating for the change therein caused by the introduction of signal'current potentials at PU or S.

While-:1 have described my invention as embodiedin an apparatus having a particular set of constants with relation to certain commercially available tubes it is to be understood that variationsin these constants are to'be construed as coming within the scope of the claims appended hereto. I Having thus described my, invention, what I A claim. is:

1.. In a direct coupled tube system; the-combina tion of a rectifier and filter system comprising a 1 source of unidirectional pulsating current; an

output tube; a resistance; the anode'to cathode path of said tube and said resistance being series connected across the terminals of said source; a pair of resistances connected between one'terminal of said source and the cathode of said output tube; a four element tube; astabilizing resistance series connected between the cathode of said four element tube and the other terminal "oi -said source; connections between the grid and screen grid of said four element tube and points of suc cessively' higher potential on said first mentioned resistance'with respect to the negative terminal of said source; a unipotential-connectionbetween' the anode of said four element tube and the grid of said output tube; and a coupling resistance connected between said unipotential connection and the point between said pair of'resistances.

2. In a direct coupled tube system, the combination of a rectifier and filter system comprising a source of unidirectional pulsating current; 'an't outputtubeya resistance, the anode to cathode path of said tube and said resistance being series connected across the terminals of said. source; a pair of resistances connected between one terminal of said source and the cathode of said output tube; a four element tube including a screen grid; a stabilizing resistance series connected between the cathode of said four element tube and .the other terminal of said source; a hum bucking condenser connected between the cathode of said four element tube and a tap on saidfirst mentioned resistance; connections between the grid and screen-grid of said four element tube and points of successively higher potential on said first mentioned resistance with. respect to the =elementtube and the other a coupling resistance connected between said unipotential connection and the point between tion of a rectifier and filter system comprising a source of unidirectional pulsating current; an

output tube; aresistance; a high frequency choke coil; said high frequency choke coil, the anode to cathode path of said tube and said resistance being series connected across the terminals of said source; a condenser of low impedance to high frequency current and high impedance to low frequency currents connected in shunt to the anode to cathode path of said output tube; a pair of resistances connected between one terminal of said source and the cathode of said output tube; afour element tube; a stabilizing resistance series connectedbetween the cathode of said four terminal of said source; connections between the grid and screengrid of said four element tube and points of successively higher potential on said first mentioned resistance with respect to the negative terminal of said source, a unipotential connection between the anode of said four element tube and the grid of said output tube and a coupling resistance.con-. nectedbetween said unipotential connection and the point between said pair of resistances.

4. In a direct coupled. tube system the combi nation of a rectifier and filter system comprising a source of unidirectional pulsating current; an output tube; aresistanceya condenser in shunt to said'resistance; the anode to cathode :path of said tube and said resistance being series connected across the terminals of said source; a pair of resistances connected between one terminal of said source and the cathode of said output tube; a four element tubeya stabilizing resistance series connected between the cathode 0 1 said four element tube and the other'terminal of said a source; connections between the grid and screengrid'of said four element-tube and points of Suecessively higher potential on said first mentioned resistance with respect to the negative terminal of said source, a unipotential connection between the anode of said four'element tube and of resistances connected between one terminal of 7 said source and the cathode of said output tube; a

condenser in shunt to said'pair ofresistances; a-

four element tube; a stabilizing resistance series connected between the cathode of said four element tube and the other terminal of said source; connections between the grid and screen-grid of said four element tube and 'points'of successively higher potential on said first mentioned resistance with .respect to the negative terminal of 7 said source, a unipotential connection between the ancde of said four element tube and the grid 01' said output tube and a coupling resistanc'econnected between said unipotential connection and the point between said pair of resistances.

' 6. In a direct coupled tube system the com bination of a rectifier and filter system compris ing a source of unidirectional pulsating current; an output tube; a resistance; the anode to cathode path of said tube and said resistance being series connected across the terminals of said source; a condenser in shunt to said resistance; a pair of resistances connected between one terminal of said source and the cathode of said output tube; a condenser in shunt to said pair of resistances; a four element tube; a stabilizing resistance series connected between the cathode of said four element tube and the other terminal of said source; connections between the grid and screen-grid of said four element tube and points of successively higher potential on said first mentioned resistance with respect to the negative terminal of said source, a unipotential connection between the anode of said four element tube and the grid of said output tube and a coupling resistance connected between said unipotential connection and the point between said pair of resistances.

7. In a direct coupled tube system the combination of a rectifier and filter system comprising a source of unidirectional pulsating current; an output tube; a resistance; the anode to cathode path of said tube and said resistance being series connected across the terminals of said source; a condenser in shunt to said resistance; a pair of resistances connected between one terminal of said source and the cathode of said output tube; a condenser in shunt to said pair of resistances; a four element tube; a stabilizing resistance series connected between the cathode of said four element tube and the other terminal of said source; hum bucking condenser connected between the cathode of said four element tube and a variable tap on said first mentioned resistance; connections between the grid and screen-grid of said four element tube and points of successively higher potential on said first mentioned resistance with respect to the negative terminal of said source, a unipotential connection between the anode of said four element tube and'the grid of said output tube and. a coupling resistance connected between said unipotential connection and the point between said pair of resistances.

8. In a direct coupled tube systemthe combination of a rectifier and filter system comprising a source of unidirectional pulsating current; an

output tube; a resistance; a condenser in shunt to said resistance; a high frequency choke coil; said high frequency choke coil, the anode to cathode path of said tube and said resistance being series connected across the terminals of said source; a condenser in shunt to said resistance; a condenser of low impedance to high frequency current and high impedance to low frequency currents connected in shunt to the anode to cathode path of said output tube; a pair of resistances connected between one terminal of said source and the cathode of said output tube; a condenser in shunt to said pair of resistances; a four element tube; a stabilizing resistance series connected between the cathode of said four element tube and the other terminal of said source;

hum bucking condenser connected between the cathode of said four element tube and a variable tap on said first mentioned resistance; connections between the grid and screen-grid of said four element tube and points of successively higher potential on said first mentioned resistance with respect to the negative terminal of said source, a unipotential connection between the anode of said four element tube and the grid of said output tube and a coupling resistance connected between said unipotential connection and thepoint between said pair of resistances.

9. In a direct'coupled electron tube system, the

including a low frequency output impedance ele ment, a radiofrequency choke coil connected between the anode of said tube and said impedance element, a condenser of low impedance to high frequency currents and high impedance to low frequency currents connected between the anode and cathode of said tube in parallel to said radio combination of a tube having an output circuit anode of said second tube and the control electrode of said first tube. V

SIDNEY Y. WHITE. 

